The present invention relates to metering systems, and, in particular, to distributed metering systems using wireless communication.
Metering is the periodic measurement of a parameter at multiple locations. For example, utility companies meter the natural gas, electricity and water consumed by households.
The collection of data from a metering system is usually performed by physical inspection of individual meters. For example, in residential areas, electrical utility companies use electromechanical meters with rotating disks to measure the consumption of electricity. Electrical utility companies send a "meter reader" to record the meter measurement about once a month. Metering of natural gas and water is handled similarly.
Utility companies often wish to charge different rates at different times. For example, an electrical utility company may wish to charge higher rates during peak hours of consumption, e.g., the morning and evening. In addition, electrical utility companies may wish to apply a penalty if a consumer exceeds a certain limit within a particular period of time. Unfortunately, electromechanical meters do not permit this objective to be achieved because they show only the cumulative consumption of electricity at the time of inspection.
The general ability to provide information about the history of a parameter at the time of inspection, e.g., something other than a cumulative total, will be referred to as profiled metering. Two basic approaches have been used to provide profiled metering.
One approach involves recording the meter measurements on paper, magnetic tape or computer memory for subsequent collection by physical inspection. The other approach is to use more complex meters that include a microprocessor, a clock and a memory. The microprocessor is preprogrammed with a particular billing schedule to increment a selected register depending on an internal clock. Again, the contents of the registers are collected by physical inspection. Unfortunately, these complex meters are expensive and unreliable. In particular, after a power failure, the clock will differ from real time and an incorrect register may be incremented.
Another problem with electromechanical meters is that meter measurements need to be gathered by physical inspection by "meter readers". The physical inspection of meters by is expensive. An automated system to electronically transmit metering information could provide considerable cost savings. However, a residential community may have tens or hundreds of thousands of meters. Even with computers, the simultaneous monitoring of tens of thousands of meters by a central computer system is difficult.